‘Fancy a quickie?’ … ‘Well, OK, but Match of the Day is on in 15 minutes.’
Photograph: Alamy

1 Time to explore

This may come as a surprise but it takes years to get really good at sex. In fact, the award-winning, much-celebrated sex guide Enduring Desire (by marital and sex therapists Michael Metz and Barry McCarthy) points to research that found that the best sex occurs in couples who have been together for 15 years or longer!

“In a one-night stand, in short-term relationships, sex can be more of a ‘performance,’” says Mike Lousada, a psychosexual therapist. “You show the ‘edited highlights’ and you go away at the end not knowing for sure what your partner experienced. ‘I’m here for a few hours, I’ve got five good moves and here they are!’”

You don’t learn much – the charge is the thrill of the unknown. In long-term relationships, that thrill diminishes (you’re waking up next to each other day in, day out) so couples have to replace it with something else. At the same time, there’s no hiding any more. All your insecurities and vulnerabilities will come to the surface in a long-term relationship. “If it’s a good one, that means really communicating and exploring, finding more pleasure and going deeper,” says Lousada.

STIs. Does she really like me? Is he weird? When was my last wax? Which pants am I wearing ? Sex outside committed relationships can come with a heap of anxieties and there is no greater turn-off than anxiety. “For women especially, if you’re distracted, if you can’t relax, it’s hard to enjoy sexual pleasure and experience orgasm,” says the clinical sexologist and relationship coach Uta Demontis. In a marriage or a long-term, committed relationship, those pressures lift and hopefully you’ve got your contraception sorted out too. “When you can finally put all those worries aside, you’re free to focus on enjoying yourself,” says Demontis.

3 You can experiment

“Trust is so important when it comes to sex,” says the psychotherapist Simon Jacobs. “The more you trust your partner, the more able you are to be fully yourself. The sexual act is one of the few moments where you let go of your inhibitions so it’s a vulnerable place to put yourself.” Kink. Taboos. If you feel safe, you’re less inhibited. “Good sex is about being able to play again, be silly, get messy,” says Jacobs. “Transgressing boundaries when you are Mr and Mrs Normal living a structured, routine kind of life – that’s where the contrast can get really interesting.”

At the same time, there should be no power games, no need to pretend if something does nothing for you. “In some relationships, in young relationships, we may be more led by Hollywood – or pornography – to do things we’d rather not or don’t enjoy,” says Emma Waring, a psychosexual nurse therapist based at London Bridge hospital. Sex in the shower. Upside down, back to front and in the sea. “They always seem to have sex very fast and standing up in movies and I wonder how easy or enjoyable that would be for a lot of couples,” says Waring. When you’re married, you’ve got the marital bed at your service. Why pretend you’d rather do it underwater?

5 You can have quickies

Every encounter isn’t charged with expectation – sex doesn’t have to be an event every time. You know each other’s shortcuts and each other’s bodies. You can do it fast, then move swiftly on to discuss the broken dishwasher or what is for tea. “You can have ‘great sex’ and ‘good enough’ sex and sex that doesn’t really leave you physically satisfied – but all of it nurtures intimacy,” says Waring. “Not taking sex really seriously and being playful is important in a marriage. I think it’s fantastic when a couple can say, ‘I fancy one.’ ‘Well, OK, but Match of the Day is on in 15 minutes.’”

6 … and sneaky ones

As life moves on, if children arrive, you are grown-up, respectable – and rarely alone. You may have to seize the moment and take your chances – and that’s fun, says the psychotherapist Christine Webber. “If you know your children are out every Saturday morning, you wave them off, close the door and make the most of it before they get back. Or you have a teenager awake upstairs who would be horrified to know what you’re up to, so you have to be quieter – all that can be pretty powerful! It’s the same as being a teenager and taking a chance when your parents are out of the room. It feels illicit – and it’s also often funny. My husband (the author and media doctor Dr David Delvin) once wrote ‘Laughter is worth 1,000 orgasms.’ I’m not sure I’d go that far but it’s certainly up there!”

Sex is a great way to de-stress and in a long-term relationship it’s always possible. Photograph: Getty Images/Hero Images

“Sex serves all kinds of purposes,” says Webber. “It can be very restorative. You can have consoling sex after a disappointment or healing sex after a horrible row. You might have sex to comfort your partner after a really bad day or distract yourself at a difficult time.”

The point is, when you’re married, it’s always possible. “I imagine, in times like these, sex is helping a lot of couples,” says Webber. “As the world seems to be unravelling before our eyes, it’s the best way of de-stressing, and of bringing that sense of safety, of belonging somewhere and having someone when times are frightening.”

8 You remember each other’s bodies at their best

“There’s something about someone making love to your body when it’s not the body it once was,” says the psychotherapist Wendy Bristow. “I’m not just talking about ‘oldies’ – you can be 35 and have just had a baby. Even if your confidence and self-esteem are fine, we all have certain bits of our bodies we’re not happy about. You may not be consciously turning a blind eye to your partner’s extra bumps and lumps and wobbly bits, but when you marry someone and the years pass, there’s still a sense that you’re making love to the person you first made love to. You hear it when an elderly man says of his wife, ‘She’s still the girl I fell in love with.’ Carrying that sense of who you both were can be wonderful.”

9 Postcoital moments mean much more

In one-night stands and short-term relationships, it can be awkward, icy or absent. In a loving marriage, it’s the icing on the cake. Christine Webber has just written a novel, Who’d Have Thought It?, about a middle-aged woman who finds herself single again after a long marriage. She finds exquisite sex and excruciating sex, but what she wants is love and marriage.

“Most people who come to my practice are there because what they really want is to find someone who’ll be there, come what may, for the rest of their life,” says Webber. “If you haven’t found that, you can have rampaging sex with a stranger and 12 types of orgasm, then go home to an empty house and that experience may not feel so great.

“If you have sex that is grounded in what the psychologists call genuine, authentic loving, when that physical pleasure is set against the backdrop that’s the bedrock of your life – that’s the lasting pleasure we want most.”

Celebratory sex when life is going well creates a deeper connection. Photograph: Getty Images

10 Celebratory sex

It’s the kind of sex that means so much more in a long marriage. An anniversary. Your son’s graduation. Your daughter’s wedding. A brilliant family holiday. “It’s really more than sex, it’s celebrating your whole story together, your appreciation of one another and what you’ve both built,” says Wendy Bristow.

“When you have sex in times of high emotion and happiness, and at significant milestones, that connection between you creates great sex and the great sex creates deeper connection. It’s a fantastic, virtuous circle – and you just don’t get it in short-term casual encounters.”

11 You’re in it together for the long haul

“I’ve worked with amazing couples faced with prostate cancer, breast cancer, who are shining examples of what an ‘intimate team’ looks like,” says Emma Waring, of London Bridge hospital. “They might have gone through a period in which there wouldn’t have been a lot of sex, because it is too painful, and body parts they used to enjoy don’t work or have changed through surgical intervention, or chemotherapy, but they have worked through that and pulled together with a shared goal because they want to have sex well into old age.

“When you’re young you may have loads of sexual energy, and your body responds as you hope, but be prepared for the fact that this might not always be the case. If you have a loving, supportive partner at your side, you have the ability to face what life brings you – and find a way around the problems.”